JP2023139479A - Load fluctuation responsive type water treatment system - Google Patents

Abstract

To provide a water treatment system which is responsive to load fluctuation in raw water.SOLUTION: A water treatment system 1 comprises two series of a first supply pipe 3A and a second supply pipe 3B, each series comprises first and second coagulation sedimentation tanks 5A, 5B, first and second relay tanks 6A, 6B, liquid feed pumps 7A, 7B, first and second neutralization tanks 8A, 8B, first and second biological treatment devices 9A, 9B, and a filtration raw water tank 10. A serial piping 14 is connected to the first supply pipe 3A on a downstream side of the liquid feed pump 7A, and this serial piping 14 communicates with a front stage of the second coagulation sedimentation tank 5B. Further, a branch piping 18 is connected to the second supply pipe 3B on a downstream side of the relay tank 6B, and merges with the first supply pipe 3A on an upstream side of the first neutralization tank 8A.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water treatment system that can process raw water in response to load fluctuations.

Conventionally, in factories for various industries, wastewater containing organic matter is treated with biological treatment such as the standard activated sludge method to reduce organic matter before being discharged. Here, the standard activated sludge method is a biological treatment method in which organic wastewater is aerobically treated biologically. In this standard activated sludge method, industrial wastewater discharged from various factories is temporarily stored in a buffer tank. The water flowing out from the buffer tank is subjected to primary treatment such as oil/water separation treatment or coagulation sedimentation treatment, and then to secondary treatment using biological treatment.

The raw water load of such factory wastewater may vary greatly due to changes in the quality of the wastewater (raw water) due to weather conditions, seasonal temperature conditions, changes in manufactured products, etc. In factories where the raw water load fluctuates widely in this way, conventionally, wastewater treatment equipment was installed for high-load and low-load use, and different wastewater treatment equipment was used to treat when the raw water load was high and when it was low.

By the way, Patent Document 1 describes a water treatment system including a plurality of identical water treatment devices, in which the denitrification process is separated into two steps, and an organic carbon source is injected into the nitrified water to remove some of the NOx-N in the nitrified water. The first denitrification step removes residual NOx-N, and the amount of organic carbon source injected into the treated water of this first denitrification step is from 0 to an amount insufficient for the growth of denitrifying bacteria to remove residual NOx-N. In a water treatment system in which denitrification means are arranged in series in two stages, the denitrification means for the first denitrification step and the denitrification means for the second denitrification step each perform a second denitrification step to obtain denitrified water. A water treatment system is disclosed in which means can be alternately switched.

Further, Patent Document 2 discloses a water purification system including a plurality of filters in which the filters can be switched between parallel and series depending on the amount of filtration.

Special Publication No. 62-31638 Japanese Patent Application Publication No. 10-43768

However, in conventional wastewater treatment systems that have wastewater treatment equipment for high-load and low-load use, it is necessary to install two types of wastewater treatment equipment, which not only increases equipment costs but also requires a large installation space. There is a problem. Another problem is that when low-load wastewater flows, high-load wastewater treatment equipment becomes idle, meaning that it cannot demonstrate its maximum capacity throughout the year.

Therefore, it is possible to deal with this by installing multiple devices of the same type as described in Patent Document 1 and Patent Document 2, but these technologies are not designed to solve the problem of water quality fluctuations. Even if this technology is applied directly to wastewater treatment equipment, it is difficult to adapt it to changes in wastewater load.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a water treatment system that can process raw water in response to load fluctuations.

In view of the above object, the present invention first provides a water treatment system comprising at least a plurality of first water treatment devices that treat raw water, the first water treatment devices treating raw water in parallel. Provided is a water treatment system, which is provided with piping and a series piping that connects the first water treatment device in series and performs series treatment, and is provided with a switching means for switching between the parallel piping and the series piping (invention 1).

According to this invention (invention 1), the flow path is switched between operating the first water treatment device in series or in parallel depending on the raw water load, and when high load raw water inflows, the first water treatment device is operated in series or in parallel. By connecting water treatment devices in series and operating them in parallel when low-load raw water flows in, it is possible to perform appropriate treatment in response to fluctuations in raw water load.

In the above invention (invention 1), it is preferable that the same number of second water treatment devices as the first water treatment devices are provided downstream of the first water treatment device (invention 2).

In the above invention (invention 2), it is preferable that the second water treatment device is provided so as to be able to process the treated water of the plurality of first water treatment devices in parallel, respectively (invention 3).

According to this invention (Inventions 2 and 3), even if the first water treatment device is operated in series or in parallel, the treated water of the first water treatment device is further processed in the second water treatment device. can be processed.

In the above inventions (Inventions 2 and 3), it is preferable to include a third water treatment device that processes the treated water of the first water treatment device or the second water treatment device (Invention 4).

According to this invention (invention 4), it is possible to construct a water treatment system capable of more advanced treatment using the first water treatment device, the second water treatment device, and the third water treatment device.

In the above invention (invention 4), a plurality of the third water treatment devices are provided in parallel, and the number of operating third water treatment devices can be switched depending on whether the first water treatment devices are connected in parallel or in series. It is preferable that (Invention 5).

According to this invention (Invention 5), even if the first water treatment device is operated in series connection or in parallel, the third water treatment device By switching the number of operations, the third water treatment device can be operated appropriately.

In the above inventions (Inventions 4 and 5), the first water treatment device is a coagulation sedimentation device, the second water treatment device is a neutralization tank, and the third water treatment device is a filter. It is preferable that there be (Invention 6).

According to this invention (Invention 6), since the raw water load greatly affects the processing capacity of the coagulation sedimentation device, the parallel piping that processes the coagulation sedimentation devices in parallel, and the series connection that connects the coagulation sedimentation devices in series to process the series in series. By providing piping and switching between parallel piping and series piping according to the raw water load, raw water can be properly treated.

Second, the present invention provides a water treatment system comprising a plurality of water treatment lines in which a plurality of different water treatment apparatuses for treating raw water are connected in series, wherein at least one water treatment line constitutes the first water treatment line. Connecting piping is provided at the downstream stage of one type of water treatment equipment to connect to the front stage of the same type of water treatment equipment constituting another water treatment system, and the water treatment equipment can be used for parallel processing or serial processing. Provided is a water treatment system comprising a switching means for switching to (Invention 7).

According to this invention (Invention 7), at least one type of water treatment device constituting one water treatment system and the same type of water treatment device constituting another water treatment system are operated in series according to the raw water load. By switching the flow paths to either operate in parallel or in parallel, and operate in series when high-load raw water is flowing in, and in parallel when low-load raw water is flowing in, the appropriate flow path can be adjusted in response to fluctuations in the raw water load. can be processed.

In the above invention (invention 7), a part of the treated water of the water treatment equipment of the other water treatment system is transferred to the downstream stage of the water treatment equipment of the other water treatment system to which the connecting pipe is connected to the front stage. It is preferable to provide a branch pipe for supplying the water treatment system to the latter stage of the water treatment device (Invention 8).

According to this invention (Invention 8), at least one type of water treatment device and the same type of water treatment device constituting another water treatment system are operated in series, and the treated water is then used in the water treatment device at the latter stage of each system. It can be disposed of appropriately.

According to the water treatment system of the present invention, it is possible to switch between parallel piping in which raw water is treated by a plurality of first water treatment devices, respectively, and series piping in which the first water treatment devices are connected in series and treated in series. Therefore, by operating the first water treatment equipment in series when high-load raw water inflows, and in parallel when low-load raw water inflows, appropriate treatment can be performed in response to fluctuations in the raw water load. It can be carried out. The present invention eliminates the need to install multiple water treatment systems even in factory equipment where the raw water load fluctuates greatly, and reduces initial costs by reducing idle equipment and reduces installation space by sharing water tanks between two lines of equipment. Effects can be obtained. Furthermore, by reducing idle equipment, running costs such as power consumption and equipment maintenance can be reduced.

FIG. 1 is a flow diagram illustrating a water treatment system according to an embodiment of the invention. It is a flowchart which shows the processing of raw water at the time of low load in the same embodiment. It is a flowchart which shows the processing of raw water at the time of high load in the same embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the water treatment system of this invention is described with reference to an accompanying drawing.

[Water treatment system]
FIG. 1 shows the water treatment system of this embodiment. In FIG. 1, a water treatment system 1 includes a raw water tank 2 connected to a first supply pipe 3A and a second supply pipe 3B as two series of parallel pipes, and a first supply pipe 3A and a second supply pipe 3B. The tube 3B has liquid pumps 4A and 4B at its base end, respectively. Each of these series includes first and second coagulation sedimentation tanks 5A, 5B, first and second relay tanks 6A, 6B, liquid feeding pumps 7A, 7B, first and second Neutralization tanks 8A, 8B, first and second biological treatment devices 9A, 9B as second water treatment devices, filtration raw water tank 10, and a third continuous water pump 12A, 12B, 12C, 12D. It is composed of four filters 11A, 11B, 11C, 11D and a filtration treatment water tank 13 as a water treatment device.

A series pipe 14 equipped with an on-off valve 15 is connected to the first supply pipe 3A on the downstream side of the liquid sending pump 7A, and this series pipe 14 is connected to the second coagulation sedimentation tank 5B of the second supply pipe 3B. It is connected to the front stage. Opening/closing valves 16 and 17 are provided downstream from the connection point of the series pipe 14 of the first supply pipe 3A and upstream of the communication point of the series pipe 14 of the second supply pipe 3B, respectively. There is. By controlling the opening and closing of these on-off valves 15, 16, and 17 as switching means, it is possible to switch the first and second coagulation-sedimentation tanks 5A and 5B between the parallel side and the series side.

Further, a branch pipe 18 having an on-off valve 19 is connected to the downstream side of the second relay tank 6B, and this branch pipe 18 is connected to the first supply pipe on the upstream side of the first neutralization tank 8A. An on-off valve 19 is provided which joins the supply pipe 3A, and joins the first supply pipe 3A on the upstream side of the first neutralization tank 8A.

In addition, the water treatment system 1 of this embodiment includes a first coagulation sedimentation tank 5A, a first relay tank 6A, a liquid feeding pump 7A, and a first inner tank, which are provided in series along the first supply pipe 3A. A first water treatment system consisting of a Japanese tank 8A, a first biological treatment device 9A, a second coagulation sedimentation tank 5B, a second relay tank 6B, which were provided in series along the second supply pipe 3B, It consists of a second water treatment system consisting of a liquid sending pump 7B, a second neutralization tank 8B, and a second biological treatment device 9B. A connecting pipe 14 is provided downstream of the relay tank 6A and connected to a second coagulation sedimentation tank 5B and a front stage of the second relay tank 6B, which are water treatment devices of the same type, and the first coagulation sedimentation tank 5A It is also possible to specify that the first relay tank 6A, the second coagulation sedimentation tank 5B, and the second relay tank 6B are equipped with a switching means for switching between the parallel side and the series side.

[How to operate the water treatment system]
A method of operating the water treatment system 1 as described above will be described below.

(How to operate at low load)
When the load of raw water W is low, the water treatment system 1 is operated in parallel. That is, as shown in FIG. 2, the on-off valve 15 of the series pipe 14 is closed, and the on-off valve 19 of the branch pipe 18 is closed.

In this state, the liquid pumps 4A and 4B are operated to supply raw water W to the first supply pipe 3A and the first supply pipe 3A, respectively. Then, in the first coagulation-sedimentation tank 5A and the second coagulation-sedimentation tank 5B, a flocculant and, if necessary, an antifoaming agent are added to carry out flocculation and precipitation processing. Next, via the first relay tank 6A and the second relay tank 6B, the liquid is sent to the first neutralization tank 8A and the second neutralization tank 8B by the liquid sending pumps 7A and 7B, where the caustic soda ( Add an alkali such as NaOH) and stir to neutralize to pH 6.5 to 7.5. Next, biological treatment is performed while aeration is performed in a first biological treatment tank 9A and a second biological treatment tank 9B, such as a fluidized bed type aerobic biological treatment tank, to decompose organic matter.

The treated water (filtered raw water) W1 of the first biological treatment tank 9A and the second biological treatment tank 9B which have been subjected to the biological treatment in this way is received in the filtered raw water tank 10 and made to join together. At this time, in parallel processing, the amount of raw water W to be processed is larger than in serial processing, which will be described later. The filtered raw water W1 is supplied to the filters 11B, 11C, and 11D of the stand, and turbidity components are removed to obtain filtered water W2, which is stored in the filtered water tank 13 to treat the raw water (wastewater) W. I can do it.

In such a low load operating method, the first supply pipe 3A series and the second supply pipe 3B series perform processing independently. During this parallel operation, by performing parallel treatment in the two series of coagulation sedimentation tanks 5A and 5B, it is possible to stably treat the water up to the discharge level while ensuring the amount of water to be treated in the entire water treatment system 1. The four filters 11A, 11B, 11C, and 11D may be operated at all times, and one may be stopped for backwashing or the like, and the filters to be stopped may be changed in sequence.

(How to operate under high load)
When the raw water load is high, the first and second coagulation sedimentation tanks 5A and 5B of the water treatment system 1 are operated in series. That is, as shown in FIG. 3, the on-off valve 15 of the series pipe 14 is opened, and the on-off valve 16 downstream of the connection point of the series pipe 14 of the first supply pipe 3A and the series pipe of the second supply pipe 3B are opened. The on-off valve 17 upstream of the communication point 14 is closed, and the on-off valve 19 of the branch pipe 18 is opened.

In this state, the liquid feed pump 4B is stopped, and the liquid feed pump 4A is operated to supply raw water W only to the first supply pipe 3A. After the first coagulation and sedimentation tank 5A adds a flocculant and, if necessary, an antifoaming agent to carry out flocculation and precipitation treatment, the treated water is fed from the first relay tank 6A by the liquid feed pump 7A. This treated water is supplied to the front stage of the second flocculating sedimentation tank 5B via the series piping 14, where a flocculant is added and the treated water is flocculated and sedimented again. The liquid is sent from the second relay tank 6B by the liquid sending pump 7B. At this time, since the branch pipe 18 is open, this treated water is sent to the second neutralization tank 8B and also to the first neutralization tank 8A. In this first neutralization tank 8A and second relay tank 6B, an alkali such as caustic soda (NaOH) is added to neutralize the pH to about 6.5 to 7.5. Subsequently, biological treatment is performed in a first biological treatment tank 9A and a second biological treatment tank 9B, such as a fluidized bed type aerobic biological treatment tank, to decompose organic matter.

The treated water (filtered raw water) W1 of the first biological treatment tank 9A and the second biological treatment tank 9B which have been subjected to the biological treatment in this way is received in the filtered raw water tank 10 and made to join together. At this time, since the amount of raw water W to be processed is small in series processing, two of the four liquid sending pumps (12C, 12D) attached to the filtration raw water tank 10 are operated to feed the two filters 11C, 11D. The raw water (waste water) can be treated by supplying the filtered raw water W1, removing suspended matter components to obtain the filtered water W2, and storing this in the filtered water tank 13.

In such a high load operation method, after coagulation and sedimentation is performed in the first flocculation and sedimentation tank 5A of the first supply pipe 3A, the process is carried out again in the second flocculation and sedimentation tank 5B of the second supply pipe 3B. Since the coagulation-sedimentation treatment is performed, impurities can be highly removed by the coagulation-sedimentation treatment. Continuous treatment in two series of first coagulation sedimentation tank 5A and second coagulation sedimentation tank 5B.Although the amount of treated water in the water treatment system 1 as a whole is reduced compared to parallel operation, high-load wastewater is also stable. It becomes possible to treat water up to the level of discharge.

Furthermore, when operating in parallel and in series, the amount of processed raw water W is higher in parallel operation and less in series operation, while the load on raw water W is lower in parallel operation and lower in series operation. Therefore, based on these and depending on the switching between series operation and parallel operation, the amount of various chemicals added in the first coagulation sedimentation tank 5A and the second coagulation sedimentation tank 5B, the first biological treatment tank 9A, The pH of the second biological treatment tank 9B may be switched using an intermittent timer to set the injection amount of various chemicals according to the wastewater load.

As described above, the water treatment system of the present embodiment can be operated in a manner that switches between high and low raw water loads, so it can be suitably applied to factories where the quality of raw water W fluctuates significantly. I can do it. Moreover, since parallel operation and series operation are possible with the same device configuration, the device can be made more compact, and by making these changes possible with an operation panel, it is also possible to improve work efficiency. The switching between parallel operation and series operation can be set as appropriate depending on the quality of the raw water W (for example, the concentration of turbid components and TOC concentration), the amount of water to be treated, and the performance of the water treatment system 1. The setting items may be sensed, and based on the measured values, it may be determined whether to operate in parallel or in series, and the switching may be done manually, or the switching may be controlled automatically by a control means. .

Although the water treatment system of this embodiment has been described above, the present invention is not limited to the above embodiment, and can be applied to wastewater treatment devices, wastewater recovery devices, or other water treatment devices with various configurations. . Further, the first biological treatment tank 9A and the second biological treatment tank 9B are not limited to the fluidized bed type aerobic biological treatment tank, but may be an activated sludge tank, a membrane activated sludge (MBR) tank, or the like. Furthermore, various changes can be made to the series piping 14, such as connecting it to the first relay tank 6A separately from the first supply pipe 3A.

1 Water treatment system 2 Raw water tank 3A First supply pipe (parallel piping)
3B Second supply pipe (parallel piping)
4A, 4B Liquid pump 5A First coagulation sedimentation tank (first water treatment device)
5B Second coagulation sedimentation tank (first water treatment device)
6A First relay tank 6B Second relay tank 7A, 7B Liquid pump 8A First neutralization tank 8B Second neutralization tank 9A First biological treatment device (second water treatment device)
9B Second biological treatment device (second water treatment device)
10 Filtration raw water tank 11A, 11B, 11C, 11D Filter (third water treatment device)
12A, 12B, 12C, 12D Liquid pump 13 Filtration treatment tank 14 Series piping 15, 16, 17 Opening/closing valve (switching means)
18 Branch pipe 19 Open/close valve W Raw water (drainage)
W1 Filtered raw water W2 Filtered water

Claims (8)

A water treatment system comprising at least a plurality of first water treatment devices that treat raw water, wherein the first water treatment devices are connected in series with parallel piping that processes raw water in parallel by each of the first water treatment devices. A water treatment system, comprising: series piping connected to the water treatment system for serial treatment, and comprising switching means for switching between the parallel piping and the series piping. The water treatment system according to claim 1, further comprising the same number of second water treatment devices as the first water treatment devices downstream of the first water treatment device. The water treatment system according to claim 2, wherein the second water treatment device is provided to be able to process the treated water of the plurality of first water treatment devices in parallel. The water treatment system according to claim 2 or 3, comprising a third water treatment device that processes treated water of the first water treatment device or the second water treatment device. According to claim 4, a plurality of the third water treatment devices are provided in parallel, and the number of operating third water treatment devices can be switched depending on whether the first water treatment devices are connected in parallel or in series. Water treatment system as described. The water according to claim 4 or 5, wherein the first water treatment device is a coagulation sedimentation device, the second water treatment device is a neutralization tank, and the third water treatment device is a filter. processing system. A water treatment system comprising a plurality of water treatment trains in which a plurality of different water treatment equipments for treating raw water are connected in series, the water treatment system comprising at least one water treatment equipment constituting the one water treatment train at a stage downstream of the other water treatment equipment. A water treatment system, comprising a connecting pipe that connects to a previous stage of a water treatment system of the same type as the water treatment system constituting a water treatment system, and comprising switching means for switching the water treatment system between parallel processing and serial processing. system. A portion of the treated water of the water treatment equipment of the other water treatment system is transferred to the water treatment equipment of the first water treatment system after the water treatment equipment of the other water treatment system to which the connecting pipe is connected to the previous stage. The water treatment system according to claim 7, comprising a branch pipe for supplying water to a subsequent stage.

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